Page 5 - 60 surgical-infection&infestations15-19_opt

96 Common Bacterial Infections in Children

usually has clinical features of tuberculosis, with anorexia, weight loss, liver abscess is drainage of the abscess, which may be performed either
low-grade fever and night sweats, but these may be absent in some cases. percutaneously under ultrasound or CT guidance. Where facilities for such
In the neck, the cold abscess usually affects the jugulo digastrics lymph treatment are not available, open drainage may be required. Complications
nodes, which are initially enlarged. Over a period of months the lymph of percutaneous drainage may be seen in nearly 4% of patients.
nodes become fluctuant and show signs of a localised abscess, but acute Staphylococcus aureus is the commonest organism isolated from
signs are classically absent. The abscess may burst if left untreated, and liver abscesses. Other organisms, such as pseudomonas, E. coli,
a persistent sinus then develops. Usually, infected patients have multiple streptococci, and even bacteroides and Candida, may be isolated
sinuses that not only cause significant disfigurement but also are a source from pus cultures. Multiple organisms are seen in a significant
of infection for other people. Paraspinal cold abscesses are usually due to number of patients. Patients with pyogenic liver abscess should be
caries of the spine. The lumbar area is mostly affected. A classic example treated with broad-spectrum antibiotics with coverage for gram-
is psoas abscess, with visible fluctuant swelling in the inguinal region. The positive, gram-negative, and anaerobic organisms. These may later
diagnosis is often easy due to the classic presentation; however, confirma- be adjusted according to the sensitivity report, but they usually need
tion is by high erythrocytes sedimentation rate, positive tuberculin test and long-term treatment. The abscess cavity gradually regresses, and thus
isolation of gram-positive rod from the pus staining. Fine-needle aspira- ultasonography may show activity for a long time, but that does not
tion cytology will help in confirming the diagnosis by the identification mean the patient has active infections.
of caseating granuloma and rarely acid-fast bacilli. Lymph node biopsy is Amoebic Liver Abscess
confirmatory and is usually taken during drainage of a large cold abscess. Amoebic liver abscess is caused by Entamoeba histolytica, which causes
Treatment of tuberculosis abscess depends upon the causative colitis with diarrhoea and colicky abdominal pain.The stools are stained
organism. Most cases are due to Mycobacterium tuberculosis, and a four- with mucus and blood, but some patients may be asymptomatic and act
drug therapy is usually curative. Many patients, after good initial response, as chronic carriers. Transmission is through the faeco-oral route. The
unfortunately stop the treatment, and these patients are at high risk of protozoa find their way through the gut mucosa into the portal circulation
developing resistant strains of Mycobacterium tuberculosis. Treatment is and into the liver, where they multiply rapidly and cause abscess forma-
then by culture and sensitivity of the pus, and treatment may have to be tion. Due to the necrosis of the liver substance, the pus has an anchovy-
given for a long time. Infections caused by atypical mycobacterium are chocolate-like appearance. The right lobe is commonly affected, but the
now on the rise due to the bovine strain of mycobacterium. Treatment is disease may involve any lobe of the liver. If the abscess is not treated in
by extensive local excision and use of erythromycin.
time, it may have a tendency to burst into the pleural and peritoneal cavi-
Post-BCG Tuberculosis Lymphadenitis ties. The consequences may be disastrous, and the patient may present
BCG is a tuberculosis vaccine. Post-BCG abscess is the name given to with severe respiratory symptoms or may go into shock. Children with
a specialised form of cold abscess seen in babies who have been vac- amoebic liver abscesses look unwell. Due to the prolonged infective pro-
cinated for tuberculosis. There is usually a history of delayed healing of cess, the patients are anorexic and lose weight, and they have abdominal
the BCG vaccination site for several weeks or months. This is followed pain, tender hepatomegaly, and fever Leukocytosis is present, and stool
by an enlargement of the regional lymph nodes and then suppuration and examination may show cysts of Entamoeba histolytica.
abscess formation. Axillary lymph nodes on the affected side are usu- Ultrasonography and CT scan will suggest the diagnosis of liver abscess.
ally involved, but other nodes (e.g., preauricular nodes) have also been Diagnosis of amoebic liver abscess can be confirmed by serological tests
affected in some patients. The baby is usually symptom free except for such as an indirect haemagglutination test or growth of organisms from
the fluctuant swelling in the axilla. Final-needle aspiration cytology will pus. Once a diagnosis is made, treatment with either oral or intravenous
show green-yellow pus with acid-fast bacilli on microscopy, and caseating metroneidazole may be started. Many amoebic liver abscesses will
granulaomas may be visible on histology in intact nodes. Treatment is by resolve with medical treatment only; however, it takes a long time and
aspiration of the nodes followed by single- or two-drug antituberculous may need external drainage. The treatment of choice for amoebic liver
therapy. The response is quick, and 3-6 months of treatment is sufficient abscess is ultrasound- or CT-guided aspiration of the abscess along with
for a permanent cure. In large abscesses, drainage or local excision of the metronidazole therapy. Some patients may need open drainage of the
affected nodes may be necessary. liver abscess if these measures fail.
Liver Abscess
Liver abscess in children is not uncommon in developing countries. Two Central Venous Line Infection
main forms are seen: pyogenic liver abscess and amoebic liver abscess. In In the paediatric population, central venous access may be required in a
adults, liver abscesses are usually seen as an extension of infections from variety of situations. With the use of small-calibre lines, such as percu-
other viscera, such as appendicitis, ulcerative colitis, hepatobiliary calculi, taneously inserted central (PIC) venous lines, the incidence of line sep-
enteric fever and penetrating injuries. In children, liver abscesses usu- sis has decreased significantly; however, incidences of line infections
ally occur from hematogenous spread. Many of these children also have in short- and long-term lines may still occur. The signs of line sepsis
underlying immune deficiencies; chronic granulomatous disease in child- may not be easy to identify in patients with other sources of infection.
hood has shown a strong association with pyogenic liver abscesses. Liver Redness over the skin, fluctuating or persistent pyrexia, and generalised
abscesses are also seen in children who are on chemotherapy or on immu- sepsis may be indicative of line sepsis. Definitive diagnosis is made by
nosuppression for transplant surgery. Rarely, liver abscesses may occur the culture of similar organisms from the peripheral blood, entry site of
after hepatobiliary surgery, such as biliary atresia and choledochal cyst. the line, and blood from the line. Any temporary line should immediately
The classic presentation of pyogenic liver abscess is high-grade fever be removed, along with treatment with broad-spectrum antibiotics. In
with chills, abdominal pain, tender hepatomegaly, and jaundice. A high patients who have had long-term lines inserted (e.g., Hickman, Broviac,
leukocyte count is suggestive, but in some patients the leukocyte count or portcath lines), salvage of the line may be attempted by giving high-
may not be very high. Nearly half of the patients will have positive dose broad-spectrum antibiotics through the line. If, however, the symp-
blood cultures. Liver function tests are often marginally deranged. toms persist, then removal of the line should not be delayed. Serious con-
Diagnosis is confirmed by ultrasonography, and a CT scan will help in sequences secondary to line sepsis include bacteria endocarditis, multiple
differentiating this from other cystic lesions. Serological tests for amoebae abscesses, and meningitis. If a line is broken or damaged with significant
may be performed to exclude amoebic liver abscess. The treatment of sepsis, it may be replaced over a guide wire under antibiotic cover.